Pathogenicity variation of 200 isolates of rice sheath blight (SB) pathogen Rhizoctonia solani AG1 ⅠA from the infected samples from provinces of Anhui and Hubei, China were analyzed by using five cultivars with different resistance to SB at the seedling stage in greenhouse. There were significant differences in pathogenicity among these tested isolates of R. solani AG1 ⅠA. The frequency of average disease index followed a normal school distribution. Based on their disease indices to the five cultivars, the isolates were classified into three distinct pathotype groups by dynamic cluster analysis, i.e. weak, moderate and strong pathotypes, accounting for 29.5%, 60.5% and 10.0%, respectively. The moderate pathotypes were dominant. Random distribution of pathotypes in different areas implied that R. solani AG1 ⅠA population was a mixture of pathotypes naturally. The Mantel testing revealed that the pathogenicity variation was not obviously correlated with the collective location. The discriminant functions of the three pathotypes were constructed based on the Bayes method. The accurate rate for discrimination was up to 95.00%. The results indicate that dynamic cluster and discriminant analysis can be used to evaluate the pathogenicity differentiation of R. solani AG1 ⅠA.
WANG Ling,HUANG Wen-wen,HUANG Shi-wen et al. Pathogenicity Differentiation of Rice Sheath Blight Pathogen Rhizoctonia solani AG-1 ⅠA Isolates from Anhui and Hubei Provinces, China[J]. , 2010, 24(6): 623-629 .
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